Waterless printing, info search...

Yes we too would like to try Toyo even as a test but here are the difficulties with this...

1 - The press has to be warm so would mean running waste for 2-3 hours with the Toyo inks, that's a lot of waste.
2 - We can't run jobs with normal ink then switch to Toyo as the by the time we have switched, the press is cool again.
3 - We can't obtain an ISO match on Toyo so using them for production jobs is a no-go even if they worked.
4 - Some users we have heard on Toyo have to lower the press temps later in the day, this sounds like a get-around to me and not a viable solution as the controls are not readily to hand for this.

This problem is beginning to get expensive anyway as we can't use the plate-save feature and we run a lot of small format work so are wasting serious money on plates at present. I have tried various expose-clean-ink-clean-run combinations and all yield the same results. The only cure it seems is to run the plates against the blanket and rollers for 1000-2000 impressions then start printing or splash the oil - clearly not a viable solution. I have turned up the pre-inking part of the plate prep system to max and this has brought a slight improvement but I'm only talking 10-20 sheets less run-up, a normal job for me would be 20 sheets-to-run-time, when in fault mode I'm looking at 200-300 sheets which means running waste which I don't have and shouldn't need to do, you also get serious duct and roller contamination.
 
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You stated in previous posts that you have had Presstek service the machine. What is their answer to your problem from Presstek? They don't build the press aside from the imaging heads, they do supply the plate material. In my opinion, judging from your Profile name (Disappointed) you are not happy with the results you are achieveing with this press at the present time. You seem to have had had a good track record with the press previously, but now you have hit a snag. Throw the ball back in their court. If they support their Press and the products then in my opinion they should dedicate someone to help you resolve the issue. In these somewhat difficult times for the printing industry, I would think that the last thing any press manufacturer wants is to lose an unhappy customer.
 
My forum name was a throwback from the very early days of owning the smaller 34di press, it really was not a happy machine in our environment and was a nightmare from day 1, since upgrading to the 52 it has been excellent mostly and is a completely different animal - built to take a hammering instead of light duties. Unfortunately I cannot change the forum name without losing the history.

Presstek are being very helpful on this issue, they have been running tests in the showroom all day today with our inks and settings in order to try and reproduce the effect. It will either result in it not happening in which case we have a mechanical error or it will happen in which case its the plates etc. They have an engineer running it along side the demonstrator so all areas are effectively covered.

As you say, since ironing out the niggles, I have been most impressed with this machine and have defended & promoted it on many forum discussions, if a machine does what I expect of it then I have a tendency to back it all the way and very strongly too. When in full running order - up until a few months ago - this machine is capable of churning out an unprecedented amount of top quality work with ridiculously low make-ready times (I am meticulous about ink curve settings etc which provide this performance)

I am confident that this glitch will be sorted, the only concern is the time factor at present. I am gathering information here there and everywhere in order that I can put my case as sensibly as possible to Presstek as and when the time arises, normally I can figure out what is happening but this one problem has defied all of my 32 years of offset knowledge ;)
 
Glad to hear you are covering all the bases and then some. Hope you get your problem resolved and share the info. There maybe someone else out there with the same issues and will learn from your findings. Good luck and Happy Printing.
 
Update...

Presstek ran our inks in the showroom but could not run enough work to reach fault temperature on the press, it takes about three hours running to reach that point, at least they tried it.

We ran all morning yesterday with the Toyo inks and could not reproduce our fault. This indicates to me that there is no mechanical fault on the press and that the fault is caused by the plates and ink we were using. One or the other has changed and made the process susceptible to toning where it wasn't before. Neither plate or ink supplier will forward any more information on their materials so we are now at a dead end.

Unfortunately we cannot simply switch to the Toyo inks as they are not ISO standard colours.

I have one more set of inks, from a company called Classic Colours to test and hope to do so today. There are no other waterless inks available to us so this situation is getting tricky now.

Will update when more info is at hand.
 
We have a visit from Van-Son technical dept booked today to test their inks again. We never had much luck with the old formulation and found it to be very quick drying on the rollers so no down-time possible and also very picky on parts of the job with straight lines etc. Maybe they have changed things over the years, we'll see today.
 
Update

Update

This week, following a total failure on a tricky job when running our preferred inks and in the light of no further assistance forthcoming, we decided to make the switch to the Van Son ink set.

This change over entailed the recalibration of all paper types on our RIP / Press set-up, this took me three days and a hell of a lot of plates and paper as it did before, mostly because there is no fixed starting point and we needed a high match to the ISO standard. I also had to re-learn the process as I had not done it for a couple of years!

This wastage was most annoying as it was not totally our choice to make the switch - we were backed into a dead-end by reasons unknown causing our previously very stable ink/press combination to become unstable and unusable.

We have however managed to obtain very high scores against the ISO standard now and I'm in a position to put some serious runs on it in the next week or two for a thorough test.

We still have the ridiculously aggressive drying properties to counter, I had my first blanket wrap-up in three years because the blankets dried while I was loading another stack in the feeder, clearly I will have to alter my running methods to stop this.

The ink is not duct-fresh without a heavy coating of anti-skin spray (something which I hate doing as it dilutes the ink) and likewise the tins will skin-up overnight resulting in higher wastage of ink when de-skinning in the morning. This also gives the possibility of hickies etc being introduced.

Now why did I become a printer????? :confused:
 
im starting to think blanket wash/water is dripping out of spray bar for roller wash-up.Eventually the tonin/scumming goes away.Perhaps the unaffected plate surface is better prepared to repel ink after 2 wash cycles.I'll keep thinkin on this.
mike
 
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The press has cooled rollers and duct and these are set at 18c. Rollers surfaces run at 19-20c when moving. Blanket surface was 36c when the plate was at 34c.


Any thoughts?[/QUOTE]

The temperatures above seem to be a bit on the cold side,
Have you thought that perhaps you are too cold at the start and the problem goes away as the temperature rises in to the correct range.
Why not try upping the initial temp to 23C or even 26c.
Keeping the temperature rise to a "flatter curve" might help. Judging from the data you have included you are getting a temperature rise of 18C. I would think your chillers are constantly running in cooling mode trying to keep up with cooling the system to the set point which is too low and so unachievable.
You might want to think about adding an oil cooler to the system as well, That stuff can get pretty warm. This heat travels into the cylinders from the journals. I have a feeling that keeping the temperature more consistent would be better than the large swings that look like the state of affairs with your system at present.
Eric also has a point regarding some form of surface contamination of the plate which gets worn off after so many revolutions.
There is no doubt that waterless printing is much sharper as the developer cuts through the surface material. There are usually two coatings of 'silicone' each with a different surface tension. The first one down is wettable by the ink and the the surface one rejects it. The tiny cavities in the surface after processing reveal the ink carrier which are filled exactly by the ink. It transfers an exact dot with little or no smearing.
I have known it in the past that an operator thought that if cold was o.k. More colder would be more better. He had the ink duct roller so cold that condensation was formed on it and the roll would simply not pick up ink.
Just a couple of thoughts hope it points you in the right direction, Good Luck.
 
The lesson learned, if you start at beginning OP says, cannot be the ink, vendor says it is the same formula, after checking 100 other variables he changes ink and bam, problem solved, in press trouble shooting you have to actually change a variable before you summarily rule it out, or blindly trust a vendor, they are trying to sell you stuff.
 
We only changed the ink because it was the only variable we could change.

There is only one plate for this press, there are no chemicals, there are very few inks.

Luckily VanSon were on the game and open to picking up the ball with a new type of ink, the existing ink manufacturers were not interested at all.
 
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